Stalking horse

A stalking horse is a figure that tests a concept with someone or mounts a challenge against someone on behalf of an anonymous third party. If the idea proves viable or popular, the anonymous figure can then declare its interest and advance the concept with little risk of failure. If the concept fails, the anonymous party will not be tainted by association with the failed concept and can either drop the idea completely or bide its time and wait until a better moment for launching an attack.

In hunting, it refers to a horse, or a figure of a horse, behind which a hunter hides when stalking game.

The term stalking horse originally derived from the practice of hunting, particularly of wildfowl. Hunters noticed that many birds would flee immediately on the approach of humans, but would tolerate the close presence of animals such as horses and cattle.

Hunters would therefore slowly approach their quarry by walking alongside their horses, keeping their upper bodies out of sight until the flock was within firing range. Animals trained for this purpose were called stalking horses. Sometimes mobile hides are used for a similar purpose.

An example of the practice figures in the 1972 film Jeremiah Johnson, when Johnson and Chris Lapp ("Bear Claw") are hunting elk in the Rockies:

Jeremiah: Wind's right, but he'll just run soon as we step out of these trees.
Bear Claw: Trick to it. Walk out on this side of your horse.
Jeremiah: What if he sees our feet?
Bear Claw: Elk don't know how many feet a horse has!

The expression is generally used in politics and business. In politics, the circumstances are an attempt to bring down a powerful leader, usually by members of their own party. In business, the circumstances are an attempt at testing the market for a potential (hostile) takeover of a business. In each case, there is the clear understanding that the anonymous party, whether a company or an individual, has a valuable reputation that could be damaged by the failure. The stalking horse is an exercise in assessing accurately the degree of risk, so that a full-blooded challenge is only mounted by the main party when there is a real likelihood of success.

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Wikipedia